Refrigeration



REFRIGERATION Filed Oct. 21, 1938 5 Sheets-Sheet 1 INVENTOR L Georg 1 .1 I BY A 4 s, wh

IATTORNEY July 29, 1941. a. A. BRACE REFRIGERATION Filed Oct. 21

, 1938 3 Sheets-Sheet 2 ATTORNEY George, A. Brace July 29, 1941. G. A. BRAcE I 2,250,945

REFRIGERATION Filed Oct. 21, 1938 3 Sheets-Sheet 3 INVENTOR George A. Brace ATTORNEY Patented July 29, 1941' George A. Brace, Winnetka, 11L, assignor to The Hoover Company, North Canton, Ohio, a corporation of Ohio Application October 21, 1938, Serial No. 236,274

23 Claims. (01. 625) This invention relates to the art of refrigeration and more particularly to a means for automatically defrosting the cooling element of a refrigerating system.

The present invention relates to a very simple construction devoid of temperature responsive or frost thickness measuring devices for periodically defrosting the evaporator of a refrigerator and for re-establishing the normal operation of the same without attention, pre-setting or preconditioning of the control mechanism by the operator. Furthermore, all the control mechanism is located outside of the food compartment and in waste space not otherwise usable.

More particularly the invention makes use of the drip water accumulating onthe evaporator.

or chilling element of the refrigerator to operate a timing device to determine the frequency of the defrosting period. This device is so constructed as to provide for widely different conditions normally encountered in the use of household and commercial refrigerators as well as the individual wishes of refrigeration users. Thus, under certain conditions of use, frost collects much morerapidly and in greater quantity than under other conditions. Also, some people prefer to defrost frequently and others less frequently.

The present invention lends itself readily to various conditions of use, and includes very simple regulating means operable by the novice.

The control is therefore very flexible in opera-- tion.

It is another object of the invention to provide means for employing a predetermined volume of the drip water to control the defrosting of the evaporator, and to provide means for automatilated during the defrosting period of the machine. Y

A number of disadvantages and inconveniences of prior household refrigerators are directly attributable to the drip collection facilities customarily provided. These consist of a drip pan mounted in some manner below the evaporator and of suflicient capacity to store at least all the drip water resulting from the greatest amount of frost and ice likely to form on the evaporatorcally disposing of all of the drip water accumucatch device is only of sufllcient depth to collect and guide the drip to a point of disposal. This drip catchdevice is readily removably mounted in position close to the bottom portion of the evaporator. The drip catch device is so formed and constructed that all drip is collected and provision is made for free passage of newly cooled air directly to the space beneath the evaporator. Another feature of my novel drip collector is that all drip is immediately conducted from the cabinet to a point of disposal, and preferably to my novel fully automatic defrosting control.

Accordingly, it is another object of the invention to incorporate a drip collection device alon with a novel fully automatic defrosting control. It is a further object of the invention to provide a cabinet construction in which the air to be refrigerated is permitted to have a free passage from the evaporator to every portion of the storage cabinet whereby to provide uniform, reliable refrigerating effect in all useful space of the machine. I

It is therefore an object of this invention to provide a fully automatic defrosting control for a refrigerator having all the foregoing characteristics as well as others which will become apparent as the description proceeds when taken in connection with the accompanying drawings in which: i

Figure 1 is a diagrammatic representation of one form of refrigerating system to whichthe invention may be applied with the control mechanism illustrated on an enlarged scale.

Figure 2 is a partial sectional view of a detail of the control mechanism.

Figure 3 is a' bottom view of a further detail of the control mechanism.

Figure 4 is a side view-illustrating the manner in which the evaporator and control mechanisms are arranged within the cabinet of a refrigerating system.

Figure 5 is a partial sectional view illustratin the manner in which the evaporator drip tray is supported therefrom. Y

Figure 6 is a perspective view partly in section and illustrating details of the drip tray.

Figure 7 is a front view illustrating the manner in which the evaporator, drip tray, and air flow control means are positioned within the refrigerator cabinet.

. The novel control mechanism and air flow control devices forming the subject-matter of the present invention may be applied to any desired type of refrigerating system; however, for purposes of illustration it is herein disclosed as being applied to a three-fluid continuous absorption refrigerating system comprising a boiler B, an analyzer D, an air-cooled rectifier R, a tubular aircooled condenser C, an evaporator E, a gas heat exchanger G, a tubular air-cooled absorber A, a

liquid heat exchanger L, a solution reservoir S,

and conduit I! to the upper portion of the absorber A. The strong solution formed in the absorber A is conducted therefrom through the conduit [3, the solution reservoir S, a conduit l4, the liquid heat exchanger L, and a conduit l which opens into the upper portion of the analyzer D. The absorption solution is circulated by bleeding a small portion of gas discharged from the 01! culating fan F through a bleed conduit I! which opens into the conduit I2 below the liquid level normally prevailing therein whereby the absorption solution is elevated into the absorber by as lift action.

The inert gas circuit is as follows: Lean inert gas is drawn from the upper portion of the absorber through a conduit l3 into the suction inlet of the circulating fan F in which it is placed under pressure discharged through a conduit l6 into the outer path of the gas heat exchanger G from which it is conducted into the bottom portion of the evaporator E through a conduit 20.

.The inert gas refrigerant vapor mixture formed in the evaporator E is conveyed therefrom through a conduit 2|, the inner path of the gas heatexchanger G, and a conduit 22 to the bottom portion of the absorber A.

The refrigerant vapor generated in the boiler passes upwardly through the analyzer D, the conduit 23 and rectifier R to the upper portion of the condenser C. The vapor is liquified in the condenser C and is discharged therefrom through the conduit 25 into the bottom portion of the evaporator E.

The liquid refrigerant discharging into the evaporator. E is propelled therethrough by the inert gas stream as it is evaporating to produce useful refrigeration. In the'absorber the refrigerant vapor content of the pressure equalizing medium refrigerant vapor mixture isabsorbed in the solution and the heat of absorption is rejected to the air flowing over the exterior of the absorber.

The boiler B may be heated in any suitable manner; however, as herein, illustra a gas burner H is provided which is supplied with fuel through a conduit 31 which includes a solenoid valve 33. A small bY-D IB 33 is provided around the solenoid valve 33 in order to maintain a small igniting or pilot flame on the burner B when th valve 33 is in closed position.

The evaporator is provided with a suitable casing 36 beneath which is supported a drip tray 3| to which reference will be made in more detail hereinafter. For the present it is suflicient to note that any -drip discharged in the evaporator is caught in the tray 3| and is discharged therefrom into a conduit 32 which includes a U-shaped liquid seal portion. The conduit 32 discharges into a syphon chamber 33 which is provided with a vent 34.- A syphon conduit 35 extends through the side wall of the chamber 33 adjacent the top wall thereof and then turnsdownward to terminate a slight distance above the bottom of the chamber 33. The other leg of the conduit 35 extends to a level below the level of the bottom portion of the chamber 33 and opens into a drip disposal and control tank 31. The tank 31 is interiorly divided by a partition 39 into a float control chamber 46 and an excess drip disposal chamber 4|. A top plate 42 provided with a suitable evaporating opening 43 overlies the upper edge of the evaporating tank 31.

The float control chamber is pierced by an upstanding heating conduit 45 through which passes the products of combustion disposal flue 46 of the boiler heater H.

A float guide tube 46 is also mounted in the float control chamber 46 and is positioned to be in open communication with the fluid therein contained.

An elongated float 50 is mounted within the guide tube 48. As is illustrated in Figure 2, the float 50 is providedv with an elongated slot 5| which receives the cross bar 52 of a T-shaped operating rod 53. The shank of the rod 53 passes through a suitable opening 54 formed through the upper end of the float 50 and communicating with the slot 5!. An L-shaped adjusting lever 56 is rigidly attached to the upper portion of the float 50 by means of a guide screw 51 which passes through an adjusting slot 56 formed in the lever 56. The lever 56 is maintained in an adjusted position by means of a small leaf spring 55 which is rigidly attached to the float 50 and bears against the roughened inner face of the lever.

The arm 59 of the lever 56 extends across the upper portion of the slot 5| and slidably embraces 59 to bind the lever 53. 'The upper end of the Y L-shaped arm 56 extends above the upper portion of the guide tube 43 and terminates in-a slightly ofl-set portion II which is adapted to abut the upper end of the guide tube, to limit downward movement of the float 56.

The upper free end of the link 53 is connected to -a snap-acting or over center mercury switch 63 which is suitably supported upon a bracket 64 mounted upon the partition '33. When the link 53 is moved upwardly, as viewed in Figure 2, the switch snaps to the closed circuit position. Movement of the link 53 downwardly, as viewed in Figure 2, snaps the switch 63 to the open circuit position.

Electrical energy is supplied to the control mechanism through a pair of wires 65 and 66. The wire 65 connects directly to one terminal of the mercury switch 63 and the other terminal of the switch is connected by means of a wire 61 to one terminal of an adjustable thermostatic switch mechanism 68 which is mounted on a suitable control panel positionedabove the evaporator. The other terminal of the switch 68 is connected directly to the circulating motor M by means of a wire 10. The circulating motor M is of the solenoid valve 28 is connecteddirectly to the supply line 66, thereby completing the electrical circuit. A manual cut-off switch 68' is connected serially with the switch 88. r

In order to regulate theamount of cooling air admitted to the space between the heating conduit 45 and the products of combustion flue 46, a pair of valve elements 15 and 16 are pivoted to the bottom portion of the tank 31 in position to regulate that opening (see Figure 3). The elements 15 and 18 are provided with engaging gear teeth I1 and 18, respectively, whereby they move in unison toward or away from engagement with the flue 46. An actuating lever 19 is pivotally secured to the valve element I5 whereby the valve may be actuated by suitable manipulation of that lever.

Referring now to Figure 4, the arrangement of the apparatus within the-refrigerator cabinet will be described. The cabinet is provided with the usual insulated top wall 80. insulated door 8|, and insulated rear wall 82 which includes a removable insulated window element 83 behind the evaporator in order that the refrigerating apparatus may be assembled away from the cabinet and can be assembledwith the cabinet simply by inserting the evaporator and panel 83 through a window formed in the wall 82. A suitable panel 84 is spaced from the rear wall 82 of the cabinet in order to form an air flue 85 therewith. It will be understood that the cabinet will also include the usual mechanism compartment in the bottom portion thereofwhich will house the boiler, ab-

sorber and solution reservoir. The condenser C is positioned in the upper rear corner of the flue 85 in position to be swept by cooling air flowing through that flue. The flue 48 terminates in a discharge nozzle 88 positioned adjacent to but spaced from the condenser C. The U-shaped discharge conduit 32 passes through the window element 83 with the U-shaped portion thereof embedded in the insulation of the window element. The syphon chamber 33 is positioned within the flue 85 just'beneath the level of the evaporator and preferably to one side of that flue in order not to interfere with free flow of cooling aid therethrough. The evaporating and control tank 31 is also positioned in the flue 85 directly beneath the vessel 33 and to one side thereof in order to allow free evaporation. through the slot 43 of the cover 42 without interference from the vessel 33. From this arrangement it will be noted that the tank 31 is in position to be swept by air flowing through the air flue 85. The tank 31 is also positioned at a point reasonably proximate to the boiler B whereby the products of combustion flowing through that portion of the conduit 46 which is embraced by the heating tube 45 are at a reasonably elevated temperature.

Referring now to Figures 5, 6 and 7 the drip tray and air cooling system will be described. As will be noted from Figure 7, the evaporator is positioned in the top central portion of the refrigerator cabinet in order that the air within the cabinet may flow upwardly along each outside thereof ,inwardly across the box-cooling section of the evaporator and downwardly along the sidewalls of the evaporator. The downwardly flowing air streams each divide into two streams,

one of which flows directly downwardly into the storage compartment and the other of which flows inwardly along the bottom wallof the evaporatorcasingfll and over the drip tray 3|.

The drip tray 3| is preferably constructed of I insulating material, such as hard rubber or glass,

- The central portion of thetray 3| is provided venient manner.

with a pair of parallel obstructions 83 which form the lower edge of air openings 34. The top edges of the openings 84 are defined by overhanging flanges 36 of the central bottom portionof the tray 3|. The upstanding flanges 96 overhang the lips 93 to prevent drip water from falling directly into the openings 94. As shown, certainevaporating conduits which extend rearwardly of casing 38 and tray 3| are provided with drip tangs 99 which direct drippings from such rearwardly extending conduits into tray 3|. The operation of the invention will now be described. During normal operation of the refrigerating system frost inevitably collects upon the evaporator due to moisture admitted when the door is open, moisture in food and moisture carried on the surface thereof. This frost accumulates to such an extent that it seriously impedes heat transfer between the evaporator and the refrigerating compartment thereby decreasing the efliciency of the apparatus. If frost accumulation is allowed to continue for any period of time it will eventually effectively prevent the maintenance of safe' temperature conditions within the storage compartment. Periodically, the machine must be de-energized in order to permitv the frost to melt from-the evaporator.

The melting of the frost produces a large body of water which must be disposed of in a' con- According to the present invention the frost drainage is not collected inthe refrigerating compartment which is the previous practice, but it is immediately drained from the shallov. drip tray 3| through the conduit 32 and into the syphon vessel 33. As an incident of the ultimate disposal ofthe drip water the same is utilized to regulate the defrosting period of the apparatus.

It will be noted from an inspection of the drawings that the circulating motor M and the solenoid valve 28 are deenergized when sufficient water has evaporated in chamber 40 to permit float 50 to actuate snap-acting switch 63 into the open circuit position. Therefore, in order to start the apparatus initially, it is necessary to flll the chamber 40 with water which will cause the float 5|! to rise until the bottom portion of the slot ,5l abuts cross arm 52 of the operating link 53 to move the same upwardly to actuate the switch 83 to closed circuit position whereupon the refrigerating system will become energized.

Once .the machine has been energized it will continue to cycle between predetermined temperature limits as determined by the setting of thermostats -68 to control the refrigerating conditions in the cabinet. However. during this period of time heat is applied to the water contained in the tank 40 by the flue 48 which causes that water to evaporate slowly. Eventually a v sufllcient quantity of the water within the float control chamber 40 will have evaporated to allow the float 50 to drop downwardly to bring the arm 53 into engagement with the cross-bar 52. Further evaporation of moisture wi l then leave the float 58 suspended upon the cross-arm 52 and it will eventually snap the switch 63 into the opencircuit position thereby tie-energizing the machine. After the machine is de-energized,

the evaporator temperature slowly r1563 until the frost is completely melted therefrom. As the frost melts from the surface of the evaporator it is discharged through the conduit 32 into the tank 33 and eventually fills that tank to the charging level of the syphon 35 which then discharges the collected drainage into the float control chamber 40. This raises the water level in the chamber 40 and the switch 63 is actuated to closed circuit position by the float 56 in the manner described before.

The syphon vessel 33 is designed to accommodate less water than that discharged through conduit 32 by ice melting from the evaporator casing 36. However, the float control chamber 40 is designed to hold less water than the quantity discharged through the syphon 35 in order to insure that the chamber 40 will be completely -filled with water when the syphon 35 has discharged the tank 33. The excess water' discharged through the syphon 35 simplyoverflows the upper edge of the partition 39 into the overflow chamber 4| from which it evaporates substantially continuously. In the event that a greater quantity of water is discharged through the conduit 32 than the quantity of water discharged through the conduit 35 thereby leaving some water in the tank 33 after switch 63 has been returned to closed position by the float 50, the residue will simply evaporate through the vent 34 during the operating period of the ma chine whereby the chamber 33 will be in .substantially dry condition when the switch 63 again de-energizes the refrigerating system for a defrosting period.

The adjusting lever 56 provides a convenient means whereby the quantity of water which must be evaporated in order to de-en'ergize the system may be regulated. For example, by lowering the cross-bar 59 with respect to the float 56 contact between the collar 60 and the cross-arm 52 will occur with a much higher water level in the float control chamber at than would be the case if the bar 53 were in its highest position. There being no adjustment of the bottom portion of the slot, the float control chamber must be filled with water to a constant level before contact occurs between the cross-arm 52 and the bottom portion of slot 5| to actuate the switch 63 to closed circuit position. The adjusting arm 59 could be utilized to vary the length of the defrosting period by varying the position thereof with respect to the float 50, for, other things being equal, the length of the defrosting period will be determined by the quantity of water it is necessary to evaporate from the float control chamber in order to actuate the switch 63 to the open circuit or defrosting position. However, there is disclosed another means of accomplish ing variations in the length of the defrosting period which is simpler to operate than the adjusting arm 56.

The length of the defrosting period canalso be controlled by changing the adjustment of the valve elements 15 and 16 through the action of the actuating arm 19. It is preferred to have the actuating arm 19 extending substantially to the side wall of the machine to be manipulated through an opening in such wall.

For example, if it is desired to have the defrosting period occur at frequent intervals, the valve plates 15 and 16 can be moved inwardly to the position in which they engage the flue 46 and prevent air flow through the space between the flue 46 and the heating tube 45. accelerate evaporation from the float control chamber 40 because there will be no flow of air around flue 46 to impede heating of the tube 45 thereby. On the other hand, if it is desired to lengthen the defrosting period, for example, from one day to a period of several days, it will only be necessary to actuate the arm 19 to position in which the valve plates 15 and 16 do not impede flow of air through the space between the flue 46 and the heating tube 45. The flow of cooling air will impede heating of the tube 45 by the flue 46 and will thus decrease evaporation of water from the float control chamber 40.

The valve elements 15 and 16 may be also used in another fashion. For example, if the air is extraordinarily humid or if foodstuffs having a very high moisture content are being refrigerated, it will be necessary to defrost the apparatus more frequently, and, for this purpose, the valve elements 15 and. 16 should be moved more nearly to closed position in order to accelerate the heating of the float chamber 40 by the flue 46. A still further adjustment provided by the valves 15 and 16 results from the fact that the heating capacity of the flue 46 on the tube 45 is also affected by the temperature of the air flowing therebetween. For example, with a constant setting of-the valves 15 and 16 the defrosting period may vary widely between winter and summer conditions when the temperature of the air flowing through the space between the tubes 45 and 46 varies respectively from approximately 70 to approximately 95. By adjusting the valves 15 and 16 with seasonal changes it is possible to obtain a constant defrosting period with a constant adjustment of the lever 56 under widely varying conditions of atmospheric temperature. r

The pilot flame carried on the burner H when the control has cle-energized the solenoid to allow closure of the valve 28 provides a constant source of heat which produces a constant-with a given setting of the lever 19rate of evaporation from the vessel 31; consequently, there is a continuous heating and evaporation of the contents of the vessel 31 though the heating rate varies with the intensity of the flame on the burner.

As will be seen from the study of Figures 6 and '7, the instant device provides a means whereby the defrosting control and drip collecting mechanism cooperates with the evaporator and the walls of the refrigerator cabinet to provide a uniform distribution of cooled air throughout the areas to be refrigerated. This eliminates the dead spot heretofore found beneath the drip trays of domestic refrigerating cabinets by reason of the fact that portions of the cooled air flow inwardly across the bottom wall of the casing 30 before flowing through the slots 94 into the area directly beneath the evaporator.

The arrangement of the drip tray herein disclosed is highly advantageous from another standpoint, namely that of space economy. In previous constructions a large deep tray is placed on a shelf beneath the evaporator. These trays consume a space equal in cross-sectional area to the bottom portion of the evaporator and sevcleanly. and simply eliminating moisture formed by the melted frost, utilizing such moisture to frosting by utilizing the melted frost drippingsas a control actuating means. Moreover, the actuation of the control provides for the ultimate and flnal disposition of the drippings which heretofore has been a serious drawback in domestic refrigerating systems. The defrosting and draining mechanism cooperates with the evaporator to provide highly efllcient distribution of cooling air within the refrigerating compartment as is explained above.

It will be understood that the invention is not limited to the particular type of refrigerating system shown but may be combined with any desired type of refrigerating system. It is not at all necessary'that the float control chamber be placed in heat exchange relationship with the air distributing flue of the refrigerating system; it may, for example, be placed in heat exchange relationship with any heat rejecting portion of the apparatus, such as the condenser, boiler, absorber or compressor, and, if desired, it may not be placed in heat exchange relationship with any heat rejecting elements, but natural evaporation may be relied upon to produce defrosting. If natural evaporation is relied upon to regulate the defrosting period, the

quantity of water to be evaporated at any given time will be less than that which would have to be evaporated in a heated system, for this purpose theadjusting lever 56 should be lowered with respect to the float 50 to decrease the quan-: tity of water to be evaporated to actuate the float.

The present invention may be applied in such fashion that the drainage mechanism forms the sole control for the apparatus and will operate to defrost the evaporator after each operating cycle. For example, the control 68 and vessel 33 may be eliminated. In this event the wire 61 will connect directly to the motor M and the conduit 32 will empty directly into the vessel 31. The adjusting lever 56 will be set to cause operation of the switch 63 in response to the collection and evaporation of the small amount of melted frost drainage produced after each operation of the refrigerating machine. The lever 19 may be set to secure the desired periodicity of operation of the machine. With the control in this condition the machine will operate until evaporation from chamber 31 drops float 50 to actuate the switch to open circuit position. The evaporator will then warm sufliciently to melt frost therefrom, the melted frost drainage will actuate the float to move the switch to closed circuit position and themachine will be reenergized.

It is desirable to chamber in heat exchange relationship with a heat rejecting element such as the waste prodcontrol the defrosting of the apparatus automatically, providing for eflicient and complete distribution of cold air within the refrigerating compartment, providing for simple and ready adjustment of the defrosting mechanism to compensate for varying conditions of use, and providing for varying length of defrosting periods. Additionally the refrigerating system may be de-energized, regulated and defrosted manually entirely independently of the automatic control mechanism by suitable manipulation of the control elements 68 and 68'. In the event that the switch 68' is actuated to de-energize the system, any accumulated frost simply melts and is discharged into the syphon chamber in the usual manner. 1

While the invention has been enumerated and described in detail various changes may be made in the arrangement, construction and proportions of the parts without departing from the spirit of the invention or the scope of the appended claims.

It is to be understood that the protection herein applied for is not confined to the particular combinations of features or elements set out in the following claims. Protection is herein applied for, for any one or more of the features or elements referred to in thefollowing claims, or described in the foregoing specifications or shown in the accompanying drawings, either independ- .ently or in combination.

. l. A re'frigeratingapparatus comprising a heat absorbing unit, means for supplying a heat absorbing medium to said heat absorbing unit, means for collecting drip water discharged from said heat absorbing unit, said collecting means being positioned in a space to allow free evapo-- ration of the collected drippings, and means utilizing the accumulation and evaporation of the place the float controllin nets of combustion flue for the reason that once the arms 56 and 19 are set in any particular position the operator may be assured that the substantially constant temperature conditions 'prevailing within the flue 46 will assure regular and constant defrosting periods without further attention to the mechanism. Though the slots 91 the objects previously enumerated of quic'kli. 75.

drip water for controlling said medium supply means. i

2. Refrigerating apparatus comprising a cool- I ing unit, means for supplying a cooling medium to said cooling unit, means for intermittently deenergizing said cooling medium supply means to defrost said cooling unit, and means actuated by melted frost drained from said cooling unit for re-energizing said cooling medium supply .means at the end of the defrosting period.

3. Refrigerating apparatus comprising a cooling unit, means for supplying a cooling medium to said cooling unit, an evaporating chamber containing water, means for de-energi n said cooling medium supply means when the water in said evaporating chamber evaporates sufficiently to lower the level thereof to a predetermined level and for re-energizing said cooling medium supply means when the water level in said evaporating chamber is raised to another predetermined level, and means for replenishing the supply of water to said evaporating vessel after deenergization of said cooling medium supply means.

4. Refrigerating apparatus comprising a cooling unit, means for supplying a cooling medium to said cooling -'unit, an evaporating chamber containing water, means'for ,de-energizing said cooling medium supply means when the water in said evaporating chamber evaporatesv sumciently to lower the level thereof to a predetermined level and for reenergizing said cooling medium supply means when the water .level insaid evaporating chamber is raisedto another predetermined level, means for replenishing the supply of water to-said evaporating'vessel after de-energization of said cooling medium supply means, said replenishing means comprising a drip tray removably mounted upon said cooling unit close- 1y adjacent the bottom thereof, and means communicating said drip tray with said evaporating vessel.

5. An absorption refrigerating system including a boiler, means for heating said boiler, a. cooling unit, an evaporating vessel, adjustable means for applying waste heat from said boiler to said evaporating vessel, means energized by changes in water level in said evaporating vessel for controlling the energization of said boiler heating means, and means for renewing the water level in said evaporating vessel.

6. Refrigerating apparatus comprising a cooling unit, means for supplying a cooling medium to said cooling unit, means for controlling the operation of said cooling medium supply means comprising a selectively adjustable time control mechanism operated by melted frost drainage from said cooling unit, and means for intermittently directing melted frost drainage from said cooling unit into said time control mechanism;

7 A refrigerating apparatus comprising an insulated cabinet, a heat absorbing unit in said insulated. cabinet, means for supplying liquid refrigerant to said heat absorbing unit, means for normally controlling the operation of said liquid refrigerant supply means in accordance with the temperature in the interior of the insulated cabinet, means for collecting drip water from said heat absorbing unit positioned outside said insulated cabinet, means utilizing the drip water for cutting out said control means for initiating a defrosting cycle, said last mentioned means being adjustable whereby the time between each defrosting cycle may be varied.

8. In a refrigerating apparatus including a heat rejecting part and a heat absorbing part, means for collecting drip water from said heat absorbing part positioned in heat transfer relationship with the heat rejecting part to cause evaporation of said collected drip water and means responsive to the accumulation of drip water to start the apparatus and responsive to the evaporation of drip water for stopping the apparatus.

9. Refrigerating apparatus comprising a cooling unit, means for supplying a cooling medium to said cooling unit, defrosting control means comprising means for collecting melted frost drippings from said cooling unit, means operative in responseto full collection of defrosting drippings for energizing said refrigerating system for normal operation, said collecting means being constructed and arranged to dissipate said drippings at a predetermined rate, and means operative to deener'gize said refrigerating system for a defrosting cycle when a predetermined quantity of collected drippings has beendissipated.

10. Absorption refrigerating apparatus comprising a cooling unit, means for supplying a cooling medium to said cooling unit, means for collecting defrosting drainage from said cooling unit constructed and arranged to dissipate such drainage at a predetermined rate, and control means operative-to de-energize said cooling me-' dium supply means when a predetermined quantity of collected 'drainage has been dissipated and to re-energize said cooling medium supply means for normal operation when the dissipated drainage has been replaced.

11. In a refrigerating apparatus including a heat rejecting part and a heat absorbing part, means for normally controlling the operation of said apparatus, means for collecting drip water from said heat absorbing part position in heat exchange relationship with said heat rejecting part to cause evaporation of collected drip water, means actuated by the evaporation of drip water to cut out said control means and by the accumulation of said drip water to restore said control means.

12. In an absorption refrigerating apparatus including a boiler, an absorber, an evaporator and means for circulating an inert medium in a closed circuit between the evaporator and absorber, means for collecting drip water from said evaporator positioned to be supplied with heat from said boiler to promote evaporation of said collected drip water, and means actuated by the accumulation and evaporation of said drip water for controlling the supply of heat to said boiler and the supply of energy to said circulating means. v

13. Absorption refrigerating apparatus comprising a boiler, an evaporator, means for heating the boiler to produce refrigerant, means for conducting refrigerant so produced in liquid phase to said evaporator, means for intermittently deenergizing said refrigerating system, means for collecting drainage produced while said system is de-energized, and means actuated by a predetermined collection of melted frost drainage for re-energizing said refrigerating system.

14. Absorption refrigerating apparatus comprising an evaporator, a boiler, means for conducting refrigerant vapor produced in said boiler into said evaporator in liquid phase, means for.

from said boiler to said float chamber to evapo rate moisture therefrom to de-energize said system for a defrosting cycle, means for varying the rate of moisture evaporated from said float chamber to vary the period between successivedefrosting cycles, and means for collecting melted frost drainage from said evaporator and for discharging the same into .said float chamber to re-energize said boiler heating means.

15. Absorption refrigerating apparatus comprising an evaporator, a boiler, means for conducting refrigerant vapor produced in said boiler into said evaporator in liquid phase, means for heating said boiler, defrosting control mechanism comprising means adapted to control the energization of said boiler heating means, float operated means for actuating said energy control means,-a float chamber, means for applying waste heat from said boiler to said float chamber to evaporate moisture therefrom to de-energize said system for a defrosting cycle, means for collecting melted frost drainage from said evaporator and for discharging the same into said float chamber to re-energize said boiler heating means, adjustable means for varying the quantity of fluid to be 4 including a boiler, an absorber an evaporator,- and means for circulating an inert medium in a closedcircuit between the evaporator and the I absorber, means for controlling the supply of energy to said circulating means, means for collecting drip water from said evaporator positioned to be supplied with heat from said boiler, means responsive to the evaporation of said drip water for cutting out said control means and to the accumulation of said drip water to restore said control means.

17. A refrigerating apparatus'comprising' a cabinet having a flue extending up one of its side walls, a heat absorbing part positioned in said cabinet, a heat rejecting part positioned in said flue, means for supplying liquid refrigerant to said heat absorbing part, means to collect drip water from said heat absorbing part positioned in said flue-to absorb heat from said heat rejecting part, and means responsive to the accumulation and evaporation of drip water for controlling said liquid supply means.

18. Refrigerating apparatus comprising a cooling unit, means for supplying a cooling medium to said cooling unit, said cooling medium supply means adapted to be de-energized to produce a defrosting cycle of ,said evaporator, andmeans actuated by melted frost drainage produced during a defrosting cycle for re-energizing said cooling medium supply meansfor normal operation.

19. Refrigerating apparatus comprising a cooling unit, means for supplying a cooling medium to said cooling unit, defrosting control means for said cooling unit comprising an evaporating vessel, means adapted to de-energize said refrigerating system when a predetermined quantity of the water in said vessel has evaporated and to re-energize said refrigerating system when such predetermined quantity of water is replaced in said evaporating vessel, means for collecting defrosting drainage from said cooling unit, and

means for discharging such drainage'into said evaporating vessel after such predetermined quantity thereof has collected.

20. Refrigerating apparatus'comprising a cabinet, a cooling air flue positioned along one wall of said cabinet, a cooling unit in said cabinet, a cooling mediumsupply meansfor said cooling unit having warm portions positioned within said air flue, means for collecting water draining from;

said cooling unit, and defrosting control means including means in said air flue for receiving water from said collecting means, and means actuated by the alternate collection and evaporation of said water for controlling the energization of said cooling medium supply means.

21. Refrigerating apparatus comprising a cabinet, a cooling air flue positioned along one wall of said cabinet, a cooling unit in said cabinet, a cooling medium supply means for said cooling unit having warm portions positioned within said air flue, means for collecting water draining from said cooling unit, defrosting control means including means in said air flue for receiving moisture from said collecting means, and means actuated by the alternate collection and evaporation of said water for controlling the energization of said cooling medium supply means, and means for varying the quantity of water which must be evaporated in order to carry said defrosting control means through an operative cycle.

22. Refrigerating apparatus comprising a cooling unit, means for supplying a cooling medium to said cooling unit, means for controlling the operation of said cooling medium supply means, an evaporating vessel, float operated means within said evaporating vessel for actuating said cooling medium supply control means, means for collecting defrosting drainage from said cooling unit, means for discharging predetermined quantities of said collected defrosting drainage into said evaporating vessel to actuate said control means, and means for evaporatlng'defrosting drainage not supplied to said evaporating control vessel.

23. Refrigerating apparatus comprising an evaporator, means for supplying a refrigerant to said evaporator, means for de-energizing said refrigerant supply means for a defrosting cycle, means for collecting melted frost drainage produced during a defrosting cycle, and means actuated by the collection of melted frost drainage during the defrosting cycle for re-energizing said cooling medium supply means for a normal refrigerating cycle.

. GEO. A. BRACE. 

